Thiosemicarbazone complexes of copper(II): structural and biological studies

The nature of metal complexes of heterocyclic thiosemicarbazones reported in the literature through 1989 have been reviewed with an emphasis on variations in stoichiometry and stereochemistry. A brief introduction is followed by a survey of the biological activity of the uncomplexed thiosemicarbazones. Next is a section on the chemical nature of thiosemicarbazones including a discussion of preparative methods, modes of coordination and isomerism. This is followed by a discussion of structural information and biological activity of the iron(III), iron(II), copper(II), cobalt(III), cobalt(II) and nickel(II) complexes of heterocyclic thiosemicarbazones. Short sections on the biological activity of other chelating thiosemicarbazones and metal complexes are also included.

Structural and physical correlations in the biological properties of transition metal heterocyclic thiosemicarbazone and S -alkyldithiocarbazate complexes

Variation in the FTIR spectra of a biomass under impregnation, carbonization and oxidation conditions

Four Schiff base complexes, [Cu2(L1)2(μ-NCS)2] (1), [Cu2(L2)2(μ-N3)2] (2), Cu[Cu(CH3COO)(L3)]2 (3), and [Zn{Zn(C3H4N2)(L3)}2(NO3)](NO3) (4) (where L1 = 2-[(pyridin-2-ylmethylimino)methyl]phenol, L2 = 1-[(pyridin-2-ylmethylimino)methyl]naphthalen-2-ol, and L3 = bis(salicylidene)-1, 3-propanediamine), were synthesized and characterized by elemental analyses, infrared spectroscopy, and single crystal X-ray determinations. Both 1 and 2 are structurally similar di-nuclear complexes, which are located at crystallographic inversion centers (with the center of the central Cu2N2 ring). In 1, each copper atom has a slightly distorted square pyramidal configuration, coordinated by two nitrogen atoms and one oxygen atom from L1 and another two terminal nitrogen atoms from two bridging thiocyanate anions. The Cu···Cu separation is 3.466(3) A. The structure of 2 is similar to that of 1, with Cu···Cu separation of 3.368(2) A. Both 3 and 4 are linear tri-nuclear complexes. In 3, the central Cu2+ ion is located on an inversion centre and has a distorted octahedral coordination involving four bridging O atoms from two Schiff base ligands (L3) in the equatorial plane and one O atom from each bridging acetate group in the axial positions. The coordination around the terminal Cu2+ ions is irregular-square pyramidal, with two O and two N atoms of L3 in the basal plane and one O atom from an acetate group in the apical position. The acetate bridges linking the central and terminal Cu2+ ions are mutually trans. The Cu···Cu separation is 3.009(3) A. In 4, the coordination configuration of the central and the terminal zinc atoms are similar to that of the 3, with Zn···Zn separation of 3.153(4) A. The three Schiff bases and the corresponding three copper complexes exhibit good antibacterial properties, while the zinc complex 4 has nearly no.



Synthesen, Kristallstrukturen und antibakterielle Wirkung von vier Schiff-Base-Komplexen von Kupfer und Zink



Die Schiff-Base-Komplexe, [Cu2(L1)2(μ-NCS)2] (1), [Cu2(L2)2(μ-N3)2] (2), [Cu{Cu(CH3COO)(L3)}2] (3), and [Zn{Zn(C3H4N2)(L3)}2(NO3)](NO3) (4)(L1 = 2-[(pyridin-2-ylmethylimino)methyl]phenol, L2 = 1-[(pyridin-2-ylmethylimino)methyl]naphthalen-2-ol und L3 = bis(salicyliden)-1, 3-propanediamin) wurden synthetisiert und mittels Elementaranalyse, IR-Spektroskopie und Einkristallstrukturanalysen charakterisiert. 1 und 2 sind strukturell ahnliche, zweikernige Komplexe, mit einem Symmetriezentrum in dem zentralen Cu2N2-Ring. In 1 haben die Kupferatome leicht verzerrte quadratisch-pyramidale Koordination und werden von zwei Stickstoffatomen und einem Sauerstoffatom von L1 und zwei anderen terminalen Stickstoffatomen zweier verbruckender Thiocyanat-Anionen koordiniert. Der Cu···Cu-Abstand in 1 betragt 3.466(3) A, der in 2 3.368(2) A. 3 und 4 sind lineare Dreikern-Komplexe. In 3 befindet sich das zentrale Cu2+-Ion auf einem Symmetriezentrum und ist verzerrt oktaedrisch von vier Brucken-O-Atomen zweier Schiff-Base-Liganden (L3) aquatorial und durch je ein O-Atom der beiden Brucken-Acetatgruppen in den Axial-Positionen koordiniert. Die Koordination der terminalen Cu2+-Ionen ist irregular-quadratisch-pyramidal mit je zwei O- und N-Atomen von L3 basal und einem O-Atom einer Acetat-Gruppe in der Apical-Position. Die Acetatbrucken, die die zentralen und terminalen Cu2+-Iions verbinden, sind wechselseitig trans positioniert. Der Cu···Cu-Abstand betragt 3.009(3) A. In 4 ist die Koordination der zentralen und terminalen Zinkatome ahnlich zu der von 3 mit einem Zn···Zn-Abstand von 3.153(4) A. Die drei Schiffschen Basen und entsprechenden drei Kupferkomplexe zeigen gute antibakterielle Eigenschaften, wahrend 4 nahezu unwirksam ist.

Syntheses, Crystal Structures, and Antibacterial Activities of Four Schiff Base Complexes of Copper and Zinc

In this work, a selective Pd(II) ions chelating resin based on 2-aminobenzaldehyde modified chitosan Schiff's base (Pd-CAZ) was synthesized through ion-imprinting technique. All the performed chemical and morphological changes during the modification and Pd(II) ion-imprinting process were investigated using instrumental techniques including FTIR, (1)H NMR, XRD and SEM. In addition, the mechanism of Pd(II) binding to the synthesized polymeric active sites was elucidated using both XPS and FTIR spectra, and the results indicated that Pd(II) ions coordinated in square planar geometry. Also, the selective extraction experiments with respect to Pd-CAZ and control non-imprinted NI-CAZ resins were performed to obtain the fundamental thermodynamic, kinetic and isotherm parameters. In all cases the adsorption was endothermic, spontaneous, fit well with pseudo-second order kinetic model and Langmuir adsorption isotherm model with maximum adsorption capacities of 275±0.4 and 114±0.2 mg/g for Pd-CAZ and NI-CAZ, respectively. Moreover, the regeneration and recovery experiments indicated that the resin maintain about 96% of its original activity after the fifth adsorption-desorption cycle, revealing the high economic value.

Ion-imprinted modified chitosan resin for selective removal of Pd(II) ions.

Co(II), Cd(II), Hg(II) and U(VI)O₂ complexes of o-hydroxyacetophenone[N-(3-hydroxy-2-naphthoyl)] hydrazone: physicochemical study, thermal studies and antimicrobial activity.

Metal complexes of schiff's base derived from salicoylhydrazine and biacetylmonoxime

Complexes of Ni(II), Co(II), Cu(II), Zn(II), Cd(II), Hg(II) and U(VI)O2 with 2-acetylpyridine-[N-(3-hydroxy-2-naphthoyl)] hydrazone (H2APHNH) have been prepared and characterized by elemental analysis, molar conductance, thermal (TG, DTG), spectral (1H NMR, IR, UV–Vis, ESR) and magnetic measurements. 1H NMR spectrum of the ligand suggests the presence of intramolecular hydrogen bonding. IR spectra show that H2APHNH is a bidentate, tridentate and/or tetradentate ligand. Thermal decomposition of some complexes ended with metal oxide as a final product. ESR spectra gave evidence for the proposed structure and the bonding for some Cu(II) complexes. Biological activity measurements were carried out.

Synthesis and magnetic, spectral and thermal eukaryotic DNA studies of some 2-acetylpyridine- [N-(3-hydroxy-2-naphthoyl)] hydrazone complexes

The synthesis and characterization of metal complexes of some dipositive metal ions with 1-valeroyl-4-phenyl-3-thiosemicarbazide (VTSC) is reported. The data of elemental analysis, molar conductivities, magnetic measurments and spectral (i.r., visible) studies have been used to elucidate the structure of the complexes. I.r spectra show that VTSC acts as a bidentate ligand and coordinates via 2NH and the enolic carbonyl oxygen (=C-OH) of the hydrazide moiety with the displacement of a hydrogen atom from the latter group. The values of molar conductivities in DMF indicate the non-electrolytic nature of all metal chelates. A tetrahedral structure is proposed for [Co (VTSC-H) Ac], square-planar for [Ni (VTSC-H) Ac] and [Cu (VTSC-H) Ac]H2O complexes, and octahedral for [Ni (VTSC-H)2. 2H2O]2H2O and [Co (VTSC-H)2.2H2O]2H2O complexes according to the data of magnetic and electronic spectral measurments.

Synthesis of Some Transition Metal Complexes Derived from 1-Valeroyl-4-phenyl-3-thiosemicarbazide

Bivalent transition metal complexes of o-hydroxyacetophenone [N-(3-hydroxy-2-naphthoyl)] hydrazone: spectroscopic, antibacterial, antifungal activity and thermogravimetric studies.

Kamal M. Ibrahim

Papers

Co(II), Cd(II), Hg(II) and U(VI)O₂ complexes of o-hydroxyacetophenone[N-(3-hydroxy-2-naphthoyl)] hydrazone: physicochemical study, thermal studies and antimicrobial activity.

Metal complexes of schiff's base derived from salicoylhydrazine and biacetylmonoxime

Synthesis and magnetic, spectral and thermal eukaryotic DNA studies of some 2-acetylpyridine- [N-(3-hydroxy-2-naphthoyl)] hydrazone complexes

Synthesis of Some Transition Metal Complexes Derived from 1-Valeroyl-4-phenyl-3-thiosemicarbazide

Bivalent transition metal complexes of o-hydroxyacetophenone [N-(3-hydroxy-2-naphthoyl)] hydrazone: spectroscopic, antibacterial, antifungal activity and thermogravimetric studies.